Fastening device



March 5, 1968 w. A. COCHRUM FASTENING DEVI CE Original Filed Sept. 21,1964 I B A United States Patent Ofilice 3,372,366 FASTENING DEVICEWilliam A. Cochrum, Bloomingdale, Ill., assignor to The Fastron Co.,Franklin Park, Ill., a corporation of Illinois Continuation ofapplication Ser. No. 397,952, Sept. 21, 1%4. This application Oct. 24,1966, Ser. No. 589,133 8 Claims. (Cl. 339272) ABSTRACT on THE DISCLOSUREA fastener including a washer for securing a wire to an electricalterminal having a threaded recess. The washer having a body with agenerally concave surface on one face and a generally convex surface onthe opposite face. The body of the washer having an axial holetherethrough to receive a screw for threading into the recess to holdthe wire between the concave surface of the washer and the terminal. Thecon-cave surface of the washer having rib means to grip the wire. Therib means being tapered to cam the wire towards the screw.

This invention is a continuation of my copending application Ser. No.397,952, filed Sept. 21, 1964, and now abandoned, and relates toimprovements in fastening devices of the type used in securing a wire toan electrical terminal. Such fasteners include a screw for threadinginto the terminal and a washer on the screw for holding the wire againstthe terminal.

In manufacturing fasteners of the type stated, the washers are firstmade and are thereafter assembled with screw blanks. The screw blanksare then successively subjected to a roll threading operation to formthe threads on the screws. The washers are designed with differentlyshaped opposed faces, one face being intended to be presented toward thethread for ultimate engagement with the wire, the other face beingintended for disposition against the head of the screw. Thisnecessitates that the washers be properly oriented prior to assemblywith the screw blanks. In one known type of high speed washerscrewassembly machine, the washers are fed to recepta-cles on a feed platethat then moves the washers successively to a screw-blank feedingstation wherein the screw blanks are dropped into the hole in thewasher. Before feeding the washers to the screw blank station, anattempt is generally made to orientate those washers which are notproperly oriented. This has not been entirely successful with washersheretofore made, since those washers were of a generally fiatconfiguration. The result was that many washers became assembled upsidedown on the screws.

It is, therefore, an object of the present invention to provide, for usein a fastener of the type and for the purpose stated, a washer that iscapable of being readily oriented automatically in the washer-screwassembly apparatus. This is accomplished in the preferred form of thepresent invention by making the washers of a shallow cup shape ratherthan flat. When a group of washers are delivered to the receptacles inthe feed plate, some have their convex faces presented upwardly and arethus properly oriented; the remainder have their concave faces presentedupwardly and are improperly oriented. Those improperly oriented washersare less stably supported than the others and are easily oriented bypassing a spring or other device across their upwardly presented edgesto flip them over. On the other hand, the properly oriented washers aresupported in a more stable manner and the spring or other device passesover them without turning them over.

In the roll threading operation, ,the metal of the screw blank is raisedabove the surface of the screw blank an 3,372,356 Patented Mar. 5, 1968amount greater than the diameter of the hole in the washer so that thethread prevents axial retraction of the Washer from the screw. However,in a roll thread the end portion of the thread is of variable diameterand diminishes to zero at the surface of the blank. Since it is the endportion of the thread that serves to retain the washer on the screw andthat portion is, in part, of smaller diameter than the hole in thewasher, there is a tendency for the washer to telescope with the smallerdiameter length of thread and jamb therewith.

Accordingly, it is a further object of the present invention to providea fastener in which the screw has a radially projecting flange-likeabutment that is axially between the thread and the head of the screwand is of a diameter sufiiciently greater than the end of the washerhole adjacent thereto to prevent retraction of the washer from the screwand at the same time allow the washer to be freely rotatable on thescrew.

It is an additonal and important object of the present invention toprovide, in a fastener of the type stated, a washer which is constructedto permit use of the fastener with a wide range of wire sizes. In thepreferred form of the invention, the hole in the washer is tapered fromthe convex to the concave face thereof. This allows the smaller diameterend of the washer hole to be sufii-ciently small to cause the washer toabut the aforementioned flange on the screw. At the same time thetapered hole permits the washer to tilt eccentrically to the axis of thescrew to accommodate large sizes of wire. The washer is also formed witha recess on its concave face coaxial with the washer hole, which resultsin thinning the body of the washer around the hole. This recess is oflarger diameter than the flange on the screw and receives same, and byreason thereof enables the washer to be used with small diameter wire.

It is also an object of the present invention to provide a washer inwhich the concave side thereof has rib means that grip one side of thewire to be fastened in the terminal, the rib means being of such extentas to prevent the edge of the washer from cutting the wire.

It is a further object of the present invention to provide a washer foruse in a fastener of the type stated in which the edges of the ribs arecontoured so as to crowd the wire away from the side of the terminal asthe washer is tightened by the screw against the wire. This prevents thewire from being forced against the side of terminal and possiblycracking it.

It is another object of the present invention to provide a washer of thetype stated which is in the shape of a regular polygon, such as asquare, and may be used in different positions or orientation around theaxis of the screw and still grip the wire properly.

The attainment of the above and further objects of the present inventionwill be apparent from the following specification taken in conjunctionwith the accompanying drawing forming a part thereof.

In the drawing:

FIG. 1 is an exploded perspective view of an electrical terminal andfastener, the latter being constructed in accordance with and embodyingthe present invention;

FIG. 2 is a perspective view of the fastener preparatory to insertion ofthe wire thereunder;

FIG. 3 is a fragmentary sectional view taken along line 3-3 of FIG. 2and with the wire in place between the washer of the fastener and theconductor at the terminal;

FIG. 4 is a fragmentary sectional view similar to FIG. 3 and showing thefastener tightened to secure the wire to the terminal;

FIG. 5 is a sectional view similar to FIG. 4 and showing the fastenerused with a small diameter wire;

FIG. 6 is a perspective view of the novel washer that forms part of thepresent invention;

FIG. 7 is a sectional view taken along line 7--7 of FIG. 6;

FIG. 8 is a perspective View of a modified form of washer that formspart of the present invention;

FIG. 9 is a sectional view taken along line 99 of FIG. 8; and

FIG. 10 is a sectional view similar to FIGS. 4 and and ShOWil'lg thefastener used to secure two wires of different sizes to the terminal.

Referring now in more detail to the drawing, 1 designates an electricalterminal member of conventional type that includes an insulated base 2of plastic or the like. The base 2 has a rectangular recess 3, thebottom of which has secured thereto a metallic contact strip 5, to whicha wire conductor 6 may be secured by a fastener 7, the latter includinga screw 9 and a metal washer 10. The contact strip 5 and the part of thebase 2 therebelow has a threaded bore 11 for receiving the screw 9.

The washer has a body 13 which is substantially square shaped with anedge 14 of a perimetral size somewhat less than that of the recess 3.The body 13 is, forthermore, of a shallow cup-shaped configuration witha generally convex face 16 and, opposite thereto, a generally concaveface 17. Centrally of the body 13 is an axially extending hole 19 ofsufficient size for loosely receiving the screw 9 with the convex face16 presented toward the head of the screw 9 and the concave face 17presented toward the threaded shank 18 of the screw. The hole 19 istapered from the convex face to the concave face 17.

The body 13 is also deformed to provide ribs 22 that project axiallyfrom the concave surface 17. In the present form of the invention thereare four ribs 22 which extend radially outwardly to the edge 14 and aredisposed so as to form, in plan view, a cross. On the concave face andcoaxial with the washer hole 19 is a recess 21 which results in athinning of the washer body 13 around the hole 19. The height or axialprojection of the ribs 22 from the concave surface 17 is variable and isgenerally tapered as at 26 from a minimum at or adjacent to the recess21 to a maximum at or adjacent to the edge of the washer with theaxially outermost edge portions of the ribs being approximately in thegeneral plane formed by the four corner points 23 which are at the outeredge 27 of the concave surface 17.

The washer 10 may be manufactured in a conventional manner and then fedto a washer-screw assembling machine where the washers are assembledwith the screw blanks. The ribs 22 are formed during the washer-makingprocess by a suitable tool that makes U-shaped deformations in thematerial of the washer, and thus leaves grooves or flutes on the convexface 17. The washers may be readily oriented in the machine since thosewashers which are resting on the convex faces 16 may be readily flippedover. When the washers are properly oriented the screw blank is droppedinto the hole 1 9, and thereafter the shank of the screw is rollthreaded. Furthermore, the roll threading dies may be shaped to rollforma radially outwardly raised annular bead or flange 24 on the shank ofthe screw blank between the end of the thread 18 and the head 20. Thisflange 24 is, however, of smaller diameter than the recess 21 to enablethe flange 24 to telescope loosely therein.

In use the screw 9 is threaded into the bore 11 to move the washer 10into the recess 3. After the washer is in the recess 3, the edge 14engages portions of the base that form two opposite sides of the recess3 to prevent the washer from turning relative to the screw. With thewire 6 placed between the washer 19 and the contact strip 5, the screw 9is tightened by a screwdriver until that rib 22 which is adjacent to thewire and which extends transversely thereof engages the wire 6 to holdthe wire 6 firmly against the contact strip 5, as shown in FIG. 4. Thetapered hole 19 enables the washer to tilt eccentrically to the axis ofthe screw a greater amount than would be possible if the hole 19 were ofuniform diameter. This permits the fastener to be used with relativelylarge diameter wires. Where small diameter wires 6a (FIG. 5) are used,the recess 21 enables the washer to shift toward the thread 18 and thuscloser to the wire 6a than would be otherwise possible. Thus, byproviding the recess 21, the washer will be able to move sufiicientlyclose to the contact strip 5 to clamp small Wire 6a.

The head 20 will apply pressure to the washer against the convex surface16 at the region 28, which is radially between the wire 6 and thelongitudinal axis of the washer. This insures that the pressure againstthe washer is applied in a generally axial direction so that the washerrib 22 is maintained in firm engagement against the wire.

Due to the fact that the ribs 22 extend axially outwardly beyond theedge 27, the wire 6 or 6a, as the case may be, will be grippedsubstantially entirely by the rib 22. The wire will be free of contactfrom the arcuate edge 27 that is sharp and constitutes the edge of theconcave face 17. Thus, the rib 22 prevents that sharp edge 27 fromcutting the wire.

The generaly tapered contour of the axial edge 26 of the rib 22 causesthe wire to be crowded toward the screw 9 rather than against the sideof the base 2. By reason thereof, the wire is prevented from exertingforce against the side of the base and possibly cracking it. This is ofparticular importance when the fastener is used in terminal members ofthe type wherein the recesses are slots open at both ends and formed byribs of plastic that project away from the part of the base at the sidesof the contact strip.

When he screw 9 is unthreaded from the base 11 to permit removal of thewire 6, the flange 24 permits the screw to rotate easily without bindingon the end portion of the thread 18 which might damage the thread.

FIGS. 8 and 9 show a modified form of washer 10a, which is similar tothe washer 10, previously described. However, in the washer 10a, theribs 220 extend radially from the recess 21 to the corners of the body13 rather than to the sides thereof, as in the washer 10. Thus, thewasher 10a, like the washer 10, may be positioned in the recess 3 in anyposition of orientation relative to the axis of the screw, and in thewasher 10a, two of the ribs 22a will bear against the wire.

In FIG. 10 the fastener is shown securing two wires 6, 6a to the contactstrip 5. These two wires may be of equal size or of unequal size, asillustrated. Preferably, one wire is on each side of the screw 9. Thegenerally tapered edges 26 of the ribs 22 crowd each wire away from itsadjacent side of the base 2.

In compliance with the requirements of the patent statutes, I haveherein shown and described a preferred embodiment of the invention. Itis, however, to be understood that the invention is not limited to theprecise construction herein shown, the same being merely illustrative ofthe principles of the invention.

What is considered new and desired to be secured by Letters Patent is:

1. A fastener for securing a wire to an electrical terminal having athreaded recess, said fastener comprising a screw having a head and athreaded shank for threading into the recess, a wire-clamping washerhaving an axial hole therethrough for loosely receiving the screw, saidhole being of such configuration as to permit tilting of the washerrelative to the longitudinal axis of said shank, radially outwardlyprojecting flange means on the shank and being of a larger diameter thanthat of the minimum diameter of the hole and cooperating with said headfor retaining the washer against retraction from the screw, said washerhaving a peripheral edge that surrounds the screw and said edgeincluding first and second pairs of parallel edge portions forcooperating with opposed parallel side parts of the terminal to preventrotation of the washer during assembly of the fastener with theterminal, one face of the washer being generally convex and said otherface of the washer being generally concave, said one face beingpresented toward said head, said faces sloping away from the region ofsaid hole toward said edge throughout substantially the entireperimetral extent thereof, rib means projecting axially from saidgenerally concave face and extending to said edge and being disposed ina pattern such that upon threading the screw into the recess with a wirein a position with either pair of said edge portions respectivelyadjacent said side parts of the terminal, the wire will be gripped bythe rib means and terminal irrespective of the orientation of the washeron the terminal and the pressure applied by the screw head to saidconvex surface will cause the washer to tilt in a direction tending tourge the wire toward said screw, the rib means being of suflicient axialextent to prevent said edge at said concave surface from cutting thewire, and said rib means are tapered from said edge toward the region ofsaid hole to facilitate camming the wire toward said screw.

2. A fastener according to claim 1 in which the hole in the washer istapered from the convex side toward the concave side to facilitatetilting of the washer.

3. A fastener according to claim 1 in which the rib means comprise fourribs and each rib extends from the hole radially outwardly to a cornerpoint of the washer.

4. A fastener according to claim 1 in which the washer has an axialrecess on said concave face and surrounding said hole and being of suchsize as to telescopically receive said flange means.

5. A washer having a body with a generally concave surface on one faceand a generally convex surface on the opposite face, said body having ahole therethrough that tapers from the convex surface to the concavesurface, the face with the concave surface having a recess thatsurrounds the hole to reduce the thickness of the body thereat, and ribmeans projecting axialy away from said concave surface and taperinggenerally from a minimum depth adjacent to the recess to a maximum depthadjacent to a peripheral edge of the body at the concave surface, saidrib means comprising four ribs, each of which extends from the recessradially outwardly to said peripheral edge of the washer.

6. A washer having a body, a peripheral edge of said body having cornerswhich define substantially a regular polygon, said body having agenerally concave surface on one face and a generally convex surface onthe opposite face, said body having an axial hole therethrough thattapers from the convex surface to the concave surface, and rib meansprojecting axially away from said concave surface with the axial extentof the rib means being at least as great as the axial extent of the edgeof the body at the concave surface, the rib means also extendingradially from the hole to the corners of the body at said concavesurface, the face with the concave surface having a recess thatsurrounds the hole to reduce the thickness of the body thereat.

7. A washer according to claim 6 in which the rib means is of variableaxial extent with the greater axial extent being adjacent to said edgeof the body and the lesser axial extent being adjacent to said recess.

8. A fastener for securing a wire to an electrical terminal having athreaded recess, said fastener comprising a screw having a head and athreaded shank for threading into the recess, a washer having a holetherethrough for loosely receiving said screw, said hole being taperedfrom one face of the washer to the other face thereof, radiallyoutwardly projecting flange means on said shank intermediate the threadand head and being of a diameter larger than that of the hole at saidother face and cooperating with the head for retaining the Washeragainst axial retraction from the screw, said washer having a peripheraledge that surrounds the screw and defines substantially a regularpolygon and is adapted to cooperate with parts of the terminal toprevent rotaticn of the washer during assembly of the fastener with theterminal, said one face of the washer being generally convex and saidother face of the washer being generally concave and having an axialrecess that surrounds the hole to reduce the thickness of the washerthereat, said recess being of such size as to be capable of looselyreceiving said flange means, four uniformly spaced apart rib meansprojecting axially from said generally concave face and extendingradially from the axial recess to the edge of the washer so that uponthreading the screw into the recess with a wire between the rib meansand the terminal the wire will be gripped by the rib means and terminal,the rib means being of sufficient axial extent to prevent the edge ofthe washer at said concave surface from cutting the wire and the ribmeans being of such generally tapered contour as to urge the wire towardthe screw.

References (literl UNITED STATES PATENTS 812,287 2/1906 Nagel 339-246 X830,572 9/ 1906 Cutter 339-246 2,712,123 6/1955 Wibell et a1 339-2463,081,507 3/1963 Gribble 339-246 X 3,141,722 7/1964 Nielson 339-2463,163,483 12/ 1964 Lineberger 339-269 X 3,167,376 1/1965 Edwards 339-269X 3,177,456 4/1965 Haydu et al 339-270 X MARVIN A. CHAMPION, PrimaryExaminer. EDWARD C. ALLEN, Examiner. PERRY TEITELBAUM, AssistantExaminer.

